Enhanced solar panels, liquid delivery systems and associated processes for solar energy systems

ABSTRACT

Fluid delivery systems and related structures and processes are provided, such as for use with water, treated water, and/or a cleaning solution, for any of cleaning, cooling or any combination thereof, for one or more solar panels in a power generation environment. Enhanced coatings are provided for the incident surface of solar panels, such as to avoid build up of dirt, scale, or other contaminants, and/or to improve cleaning performance. Reclamation, filtration, and reuse structures are preferably provided for the delivered fluid, and seal structures may preferably be implemented between adjoining panels, to minimize loss of the delivered water or cleaning solution. The fluid delivery system may preferably be linked to an automated control system, such as but not limited to integrated DMPPT modules and related systems.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/389,951, filed Feb. 10, 2012, which is a U.S. national entry to PCTPatent Application No. PCT/US2010/045352 filed 12 Aug. 2010, and claimspriority to U.S. Provisional Application No. 61/234,181, filed 14 Aug.2009, and is a continuation-in-part of U.S. patent application Ser. No.12/842,864 filed 23 Jul. 2010, now U.S. Pat. No. 8,035,249, all of whichare incorporated herein in their entirety by this reference thereto.

FIELD OF THE INVENTION

The present invention relates generally to the field of power invertersystems. More particularly, the present invention relates to distributedpower system structures, operation and control, and enhanced invertersystems, structures, and processes.

BACKGROUND OF THE INVENTION

Solar power is a clean renewable energy resource, and is becomingincreasingly important for the future of this planet. Energy from theSun is converted to electrical energy via the photoelectric effect usingmany photovoltaic cells in a photovoltaic (PV) panel. Power from a PVpanel is direct current (DC), while modern utility grids requirealternating current (AC) power. The DC power from the PV panel must beconverted to AC power, of a suitable quality, and injected into thegrid. A solar inverter accomplishes this task.

It would be advantageous to provide a structure, system and process toimprove the efficiency of power inverters, such as for a solar panelsystem. Such a development would provide a significant technicaladvance.

To maximize the amount of power harvested, most solar inverters performa maximum power point tracking (MPPT) algorithm. These algorithms treatan entire array of PV panels as a single entity, averaging all of the PVpanels together, with a preference towards the weakest link.

It would therefore also be advantageous to provide a structure, systemand process, to maximize efficiency and harvest capabilities of anysolar PV system, to capitalize on profit and maximum return for theowner of the system.

Three specific examples of DC energy sources that currently have a rolein distributed generation and sustainable energy systems arephotovoltaic (PV) panels, fuel cell stacks, and batteries of variouschemistries. These DC energy sources are all series and parallelconnections of basic “cells”. These cells all operate at a low DCvoltage, ranging from less than a volt (for a PV cell) to three or fourvolts (for a Li-Ion cell). These low voltages do not interface well toexisting higher power systems, so the cells are series connected, tocreate modules with higher terminal voltages. Paralleled modules thensupply increased power levels to an inverter, for conversion to ACpower.

These long strings of cells bring with them many complications. Whilethe current exemplary discussion is focused on PV Panels, other powersystems and devices are often similarly implemented for other sources ofDC power.

A problem occurs when even a single cell in a PV array is shaded orobscured. The photocurrent generated in a shaded cell may drop to around23.2% of the other cells. The shaded cell is reverse biased by theremaining cells in the string, while current continues to flow throughthe shaded cell, causing large localized power dissipation. This poweris converted to heat, which in turn lowers the panel's output powercapability. Bypass diodes, generally placed in parallel around each 24cells (which may vary between manufacturers), limit the reverse biasvoltage and hence the power dissipation in the shaded cell, to thatgenerated by the surrounding half panel. However, all the power fromthat sub-string is lost, while current flows in the bypass diode. Aswell, the bypass diode wastes power from the entire string current,which flows through the panel. The output voltage of the entire stringis also negatively affected, causing an even larger imbalance in thesystem.

Conventional module MPP currents may become unbalanced for otherreasons. PV panels in a string are never identical. Because each PVpanel in a series string is constrained to conduct the same current asthe other PV panels in the string, the least efficient module sets themaximum string current, thereby reducing the overall efficiency of thearray to the efficiency of this PV panel. For similar reasons, PV panelsin a string are conventionally required to be mounted in the sameorientation, and to be of identical size. This is not always possible ordesirable, such as for aesthetic or other architectural reasons.

In standard solar array wiring, several series strings of solar panelsare wired in parallel to each other to increase power. If there is animbalance between these paralleled strings, current flows from thehigher potential strings to the lower potential strings, instead offlowing to the inverter. Just as it is important to match the cellswithin a panel, it is also necessary to match the panels in a string,and then to match the strings, for maximum harvest from the solar array.If small fluctuations in environmental conditions occur, it can have alarge impact on the system as a whole.

Solar inverters also “average” the entire array when they perform aconventional MPPT function. However, it is not a true average, sincethere is a preference that leans towards the weakest link in the system.This means that, even though some panels may be capable of supplying 100percent of their rated power, the system will only harvest a fraction ofthat power, due to the averaging effect of the algorithm, and thecurrent following through the weaker string, panel, and/or cells.

It would therefore be advantageous to provide a means for applying analgorithm that maximizes the harvest of power from a string, panel,and/or cells. Such an improvement would provide a significant advance tothe efficiency and cost effectiveness of power cells structures,processes, and systems.

While solar panels often provide a cost effective and sustainable sourceof electricity, solar panels need frequent cleaning, up to four times ayear, depending on their location and environment. Dirt and dustbuild-up on the panels prevents sunlight from reaching the silicon,reducing electrical output by up to twenty five percent.

For one prior installation, after a six-month period with no cleaning, a25 percent increase in electrical output was achieved after washing forone group of solar panels, as compared to a similar neighboring group ofpanels without cleaning.

While thorough cleaning can increase the output of many solar panelinstallations, many prior methods and systems do not yield adequateresults, or require costly and/or labor intensive operations.High-pressure wash systems often prove to be very ineffective and leavemuch of the panel dirty, as well as requiring lots of water.Low-pressure water systems, with soft bristle brushes, require thoroughmanual scrubbing. While a low-pressure system may be very effective,they are typically labor intensive.

SUMMARY OF THE INVENTION

Fluid delivery systems and related structures and processes areprovided, such as for use with water, treated water, and/or a cleaningsolution, for any of cleaning, cooling or any combination thereof, forone or more solar panels in a power generation environment. Enhancedcoatings are provided for the incident surface of solar panels, such asto avoid build up of dirt, scale, or other contaminants, and/or toimprove cleaning performance. Reclamation, filtration, and reusestructures are preferably provided for the delivered fluid, and sealstructures may preferably be implemented between adjoining panels, tominimize loss of the delivered water or cleaning solution. The fluiddelivery system may preferably be linked to an automated control system,such as but not limited to integrated DMPPT modules and related systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary enhanced power modulecomprising a plurality of power cells connected to a distributed maximumpower point tracking module;

FIG. 2 is a schematic view of an exemplary enhanced solar panelcomprising a plurality of solar cells and a distributed maximum powerpoint tracking module;

FIG. 3 is a schematic view of an exemplary photovoltaic solar cellhaving DC output power connections to a DMPPT module;

FIG. 4 is a schematic view of an exemplary solar array comprising aplurality of enhanced solar panels;

FIG. 5 is a schematic block diagram of an exemplary solar panel systemhaving a plurality of strings of enhanced solar panels routed through acombiner box and controlled through a modular power module housinghaving one or more enhanced inverter modules;

FIG. 6 is a schematic block diagram of an alternate exemplary solarpanel system having a plurality of strings of enhanced solar panelshaving string-level combiner modules and routed through a combiner boxand controlled through a modular power module housing having one or moreenhanced inverter modules;

FIG. 7 is a block diagram of an exemplary distributed MPPT circuit;

FIG. 8 is a first graph showing exemplary current-voltage (IV) curves ofphotovoltaic solar panels over a range of temperatures;

FIG. 9 is a second graph showing exemplary current-voltage (IV) curvesof photovoltaic solar panels over a range of temperatures;

FIG. 10 is time chart of voltage output for an enhanced power modulehaving DMPPT module;

FIG. 11 is a flowchart of an exemplary operation of an enhanced powermodule having a DMPPT module;

FIG. 12 is a schematic view of an exemplary solar array comprising aplurality of solar panels, wherein a portion of the panels in one ormore strings further comprise DMPPT modules;

FIG. 13 shows the relative proportion and size of an exemplary solararray having a capacity of approximately 170 W, comprising a pluralityof enhanced solar panels, wherein a portion of the panels in one or morestrings further comprise DMPPT modules;

FIG. 14 is a block diagram of a modular power module housing having oneor more enhanced inverter modules, a central interface, and connectableto one or more local or remote monitoring or control devices;

FIG. 15 is a block diagram of a modular power module housing having twosub-modules installed;

FIG. 16 is a block diagram of a modular power module housing havingthree sub-modules installed;

FIG. 17 is a block diagram of a modular power module housing having afour sub-module installed;

FIG. 18 is a simplified schematic circuit diagram of an exemplary powersection for an enhanced inverter module;

FIG. 19 shows resultant output power signal properties for activeelimination of harmonics by inverter signal modification usingsine-weighted pulses;

FIG. 20 is a schematic circuit diagram of an exemplary self-powersection of a DMPPT module;

FIG. 21 is a schematic circuit diagram of an exemplary boost circuit fora DMPPT module;

FIG. 22 is a schematic circuit diagram of an exemplary current sensorfor a DMPPT module;

FIG. 23 is a schematic circuit diagram of an exemplary voltage sensorfor a DMPPT module;

FIG. 24 is a schematic circuit diagram of an exemplary output safetyswitch for a DMPPT module;

FIG. 25 is a schematic circuit diagram of an exemplary crowbar circuitfor a DMPPT module;

FIG. 26 is a schematic block diagram showing microprocessor-basedenhancement of an inverter, such as to eliminate one or more levels ofharmonics;

FIG. 27 is flowchart of exemplary operation of an enhanced inverter;

FIG. 28 is an exemplary user interface for monitoring and/or control ofan enhanced power harvesting system comprising power modules havingDMPPT modules;

FIG. 29 shows an enhanced power harvesting system located on the Earth,wherein one or more panels within a string have different angles and/ororientations;

FIG. 30 is a partial cutaway view of an enhanced solar panel structurehaving a top coating layer;

FIG. 31 is a simplified schematic view of an array of enhanced solarpanels having a rack mounting angle;

FIG. 32 is a simplified schematic view of a first exemplary embodimentof a fluid delivery system for array of enhanced solar panels;

FIG. 33 is a detailed schematic diagram of a second exemplary embodimentof a fluid delivery system for array of enhanced solar panels;

FIG. 34 is a simplified schematic view of a third exemplary embodimentof a fluid delivery system for array of enhanced solar panels;

FIG. 35 is a schematic block diagram of an exemplary liquid distributionsystem integrated with an exemplary solar panel system having aplurality of strings of enhanced solar panels routed through a combinerbox and controlled through a modular power module housing having one ormore enhanced inverter modules;

FIG. 36 is a chart that shows power reduction as a function of dirtaccumulation for a solar panel structure;

FIG. 37 is a chart that shows power output as a function of temperaturefor a solar panel structure;

FIG. 38 shows a simplified process for activation of a solar systemcooling system based upon temperature monitoring;

FIG. 39 shows a simplified process for activation of a solar cleaningsystem based upon efficiency monitoring;

FIG. 40 is a partial cutaway view of a first exemplary seal structurebetween enhanced solar panels;

FIG. 41 is a partial cutaway view of a second exemplary seal structurebetween enhanced solar panels;

FIG. 42 is a partial cutaway view of a third exemplary seal structurebetween enhanced solar panels;

FIG. 43 is a schematic view of exemplary conventional solar panelsconnected in series;

FIG. 44 is a schematic view of exemplary solar panels having DMPPTconnected in parallel; and

FIG. 45 is a schematic view of exemplary solar panels having DMPPTconnected in series.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a schematic view of an exemplary enhanced power module 10comprising a plurality of power cells 12, e.g. 12 a-12 n, such as butnot limited to photovoltaic solar cells, fuel cells, and battery cells,connected 16,17 to a distributed maximum power point tracking (DMPPT)module 18. FIG. 2 is a schematic view of an exemplary enhanced powerstructure 10, e.g. an enhanced solar panel 10, comprising a plurality ofsolar cells 12 and a distributed maximum power point tracking module 18.FIG. 3 is a schematic view 30 of an exemplary photovoltaic solar cellhaving DC output power connections 17 to a DMPPT module 18. FIG. 4 is aschematic view of an exemplary solar array 34 comprising a plurality ofenhanced solar panels 10, e.g. 10 a-10 k, arranged in a plurality ofstrings 36, e.g. 36 a-36 n.

The exemplary DMPPT module 18 seen in FIG. 1 has DC inputs 17, and a DCoutput 21, such as comprising a positive lead 19 a and a negative lead19 b, The exemplary DMPPT module 18 also comprises a communicationsinterface 20, and means for connection to a temperature sensor 24, suchas responsive to a local panel temperature 23.

DMPPT modules 18, such as seen in FIG. 1, are preferably locally poweredfrom the solar panel 10 that they are attached to, wherein each DMPPTmodule 18 draws its operating power from it's respective panel 10 thatit is connected to, such as to reduce wiring and to improve efficiency.

DMPPT modules 18 are currently implemented for both new panels 10, i.e.at the point of manufacture, and for existing systems, wherein the DMPPTmodules 18 may be retrofitted to existing panels 10. As also seen inFIG. 1, the external DC connection 21, comprising leads 19 a, 19 b, issimilar to the input DC connection 17, such as provided by an existingconventional panel. Therefore, wiring for the DMPPT modules is similarto conventional solar panels, which minimizes the learning curve forinstallation personnel.

The communications link 22 shown in FIG. 1 may be a wired connection ora wireless connection, such as to provide flexibility in design andinstallation. For example, the DMPPT module 18 can communicate via awireless network, or through a wired connection, e.g. single twistedpair standard RS485 cable.

Some embodiments of either the wired or wireless style DMPPT modulesfeature a self-discovery function, such that when a new DMPPT module 18is added to a system 40 (FIGS. 5, 6, 14), the system server 153 (FIG.14) discovers the new module 18 over the communications link 22, andadds the new module 18 and associated panel 10 to the system 40.

As well, some embodiments of wireless style DMPPT modules 18 feature aself-healing function, wherein a DMPPT module 18 having a wirelesscommunication link 22 also has the ability to bypass non-functioningdevices or branches.

For example, if a DMPPT Module 18 is broken or removed, such as by athief, in a wireless system 40, everything continues to function. Thesystem 40 sees the “broken” device 18, and continues normalcommunications with the other DMPPT modules 18. This ensures continuouscommunications with the other active DMPPT modules 18 in the system 40.In a wired system, this may typically cause the loss of communicationswith several modules 18, as the communications line 22 could be damaged,broken, or cut. In addition to the DMPPT modules 18 and inverters 54,other devices may preferably be connected to the wireless network 22. Ifsomething should happen to one of these, it will not affect the system40 as a whole. Therefore, some system embodiments 40 comprise aself-discovery module, such as provided through the server 153, builtinto the software. As well, the system 40 can be expanded to includeutility monitoring and other applications.

In a conventional solar panel system, solar cells 12 are typicallymatched to make efficient solar panels, and solar panels are typicallymatched to make efficient solar arrays. In a conventional solar system,the output of a solar array having a plurality of conventional solarpanels, i.e. without DMPPT modules 18, can never match the sum of themaximum power of the conventional solar panels, and the conventionalpanels can never match the sum of the maximum power of the solar cells12. In additional to such inherit losses of power, environmentalconditions, e.g. such as but not limited to the time of day, season,weather, location, panel positioning, panel age, and/or panel condition,further degrade the short-term and/or long term efficiency of suchsystems.

FIG. 5 is a schematic block diagram of an exemplary solar panel system40, e.g. 40 a, having a plurality of strings 36, e.g. 36 a-36 n, ofenhanced solar panels 10, e.g. 10 a-10 k, routed through a combiner box48 and controlled through a modular power module housing 50 having oneor more enhanced inverter power modules 54, e.g. 54 a-54 j. FIG. 6 is aschematic block diagram 60 of an alternate exemplary solar panel system40 b having a plurality of strings 36, e.g. 36 a-36 n of enhanced solarpanels 10 having string-level combiner modules 62, routed through acombiner box 48, and controlled through a modular power module housing50 having one or more enhanced inverter power modules 54, e.g. 54 a-54j.

FIG. 7 is a block diagram of an exemplary distributed MPPT circuit 70for a distributed maximum power point tracker (DMPPT) module 18, whichtypically comprises an integrated or retrofitted module 18 for eachenhanced solar panel 18. DMPPT modules 18 associated with the enhancedsolar panels 10 overcome several problems inherent with conventionalsolar panels and the harvesting of power.

An input filter 74 is preferably attached to the input 72 of the DMPPTmodule 18, to help reduce EMI/RFI, as well as to supply protection fromsurges, etc. on the input side. This also helps in impedance matchingbetween the solar panel 10 and the DMPPT module 18, such as to improveMPPT tracking.

The exemplary DMPPT module 18 shown in FIG. 7 preferably comprises oneor more boost inductors 76, such as a dual inductively-coupled linkinductor 76 to boost the efficiency of the DC-DC conversion stage. Thishas the added benefit of splitting the power path, which provides anincrease in efficiency. At the present time, small inductor units 76cost less and weigh less than a single inductor design, and there isless chance for core saturation. Another benefit of this design is theincreased compensation factor. This allows a more stable distributed DCBus 42,52 to be produced, with less requirements for DC-ripple andoutput filtering 86.

Some DMPPT embodiments 18 use a multi-phase approach, wherein thecontroller 80 can reduce the current flow through the power switch 78,thus increasing efficiency and reducing the heat dissipation load. Thisalso allows the DMPPT 18 to improve power harvesting of the solar panels10. The controller 80 controls the switching of these power devices 78in a modified spread-spectrum switching scheme, to minimize EMI/RFIradiation of the modules 18. Low loss switching devices 78 are used toimprove overall efficiency. In some embodiments 18, these switchingdevices 78 comprise transistors, FETs, MOSFETs, IGBTs, or any otherpower-switching device 78 that meets the design criteria.

Two diodes typically provide rectification 84 for the DMPPT modules 18,thus reducing the power dissipation and providing a plurality of pathsfor the power flow. The rectification diodes 84 also effectively isolateeach DMPPT module 18 and associated solar panel 18 from the system array30, in case of total panel failure. Even if a DMPPT module 18 fails,this isolation still exists, if it was not the diodes 84 or the outputfilter 86 that failed. This increases the reliability of the system 40as a whole.

As seen in FIG. 7, a filter 86 is preferably attached to the output ofthe DMPPT modules 18, to help reduce EMI/RFI, and to provide protection,e.g. from surges, on the output side 90. The output filter 86 also helpsto stabilize the distributed DC bus 42,52 that feeds the solarinverter(s) 54.

The controlled production of DC output voltage at the DMPPT modules 18,having a higher voltage than the incoming voltage from the panels 10,reduces power transmission losses from the array 36 to the inverter(s)54. For example, for a higher voltage DC output that is also stabilized,to get the same amount of power from the array 36 to an inverter 54requires less current, since the power loss in the conductors is givenas I²R, where I is the current over the conductors, and R is theresistance. Therefore, the lower current due to the higher voltageresults in less line drop losses, and more power to the inverter(s) 54.

In addition, the inverters 54 run at better efficiency with a stable DCDistributed Bus 42,52. While other conventional inverters experiencebetter efficiency with a higher DC Bus input, as long as it is withinthe design specifications, the DMPPT module 18 may preferably boost thedistributed DC voltage from the array 36, to maximize this benefit.

FIG. 8 and FIG. 9 show typical Current-Voltage (IV) curves ofphotovoltaic solar panels. These demonstrate how the voltage moves overa wider range than the current with temperature and solar radiation. Themaximum power point for one or more panels moves during the day, andeach panel experiences different environmental conditions, even withinthe same system. The distributed maximum power point tracking modules 18and associated inverter system 40 provide several means to maximize thepower output over a wide range of such conditions.

The panel temperature 23 (FIG. 1) is monitored and reported back to aserver, such as an embedded server 153 associated with the inverterhousing 50, or to a server 55 associated with a particular inverter 54.This temperature value is also used as an input to the multi-level MPPTcontroller 80 (FIG. 7). An op-amp may preferably be used to scale thisvalue to be read by the controller 80, and is used as another controlinput to the controller 80 of the DMPPT module 18. In some embodimentsof the DMPPT modules 18, a lead wire and temperature sensor 24 exit fromthe DMPPT Module 18 and attach to the panel 18. In alternateembodiments, a temperature sensor 124 is collocated with the DMPPTmodule 18, such as inside a panel junction box.

The embedded server 153 may preferably supply an ambient temperature,such as taken outside of the inverter cabinet 54, or outside a webserver box, such as if another inverter is used at the site.

Operation of Distributed Maximum Power Point Tracking Modules.

FIG. 10 is time chart 112 showing operation states of the DMPPT 18,indicating DMPPT input voltage 102 i, and output voltage 102 o for anenhanced power module 10 having a DMPPT module 18. FIG. 11 is aflowchart of an exemplary process 122 for operation of an enhanced powermodule having a DMPPT module 18.

As a solar panel 10 starts producing a voltage 102 and current 104 whenlight is shining on it, this power is transferred to the distributed bus42 (FIG. 5) when it exceeds the voltage 102 to overcome the componentdrops and the forward voltage drop of the diode(s), such as shown in thediode circuits D2 and D3 seen in FIG. 21. In this regard, the systembehaves like a conventional solar panel array structure. In someembodiments of solar panels 10 having DMPPTs 18, once the voltage on thesolar panel 18 reaches a threshold voltage 116 (FIG. 10), e.g.approximately 4.5 to 6.5 Volts DC, the DMPPT Module 18 automaticallywakes up 126 (FIG. 11), and starts performing the necessary checks128,130, before switching over to RUN Mode 132.

As the voltage 102 of the solar panel 18 increases, the DMPPT 18 startsboosting the voltage 102 from the panel 18 to the common distributionbus 52 feeding the solar inverters 54. This wait is necessary to preventthe loss of control power from the controller circuit 70 (FIG. 7) whenswitching begins. By using control inputs, the system tracks the maximumpower point of the solar panel 18, and boosts the voltage out to thedistributed DC Bus 52 feeding the solar inverter(s) 54.

Since the voltage 102 i is boosted 102 o, the system as a whole reachesstriking voltage for the solar Inverter 54 in a shorter period than aconventional array of panels 10 would without DMPPT Modules 18.

Furthermore, the system 40 as a whole operates longer before shuttingdown at the end of a power generation period 118, e.g. such as atsunset, dusk or evening 119 for externally mounted solar panels 18.Since the function of maximum power point tracking (MPPT) is performedat the panel level, several other issues associated with solar panels 10are addressed as well.

For example, problems with mismatched or different manufacturers can beeliminated with the DMPPT units 18. As seen in FIG. 29, solar panels 10on different planes and orientations can be combined into the samesystem, without any de-rating or loss of harvest from the array 34. Theoverall efficiency of the array is increased, because the MPPT is doneon a per panel basis, and not on the average of the entire system. Incontrast to conventional solar systems, string mismatches are not anissue, due to the active nature of the DMPPT Modules 18. Conductionlosses are reduced, thus allowing more energy to be harvested andtransmitted to the inverter 54 for grid conversion. The overallefficiency of the array 34 is increased, because the panel output isprocessed, monitored, and controlled on a per panel basis, and not basedupon the average of the entire string 36 or array 34. Safety featuresare built into the design for fire safety, monitoring, and several otherfuture applications.

Overall, the DMPPT Module 18 addresses many of the current limitationsof solar power, such as by providing longer harvest times withpanel-level DMPPT modules 18, by providing “Early-On” and “Late-Off” forextended harvest times. Since the output from the solar panels 10 isboosted, the usable power is converted by the inverter 54, because thestriking voltage is reached sooner and can be held longer, therebyresulting in an increase in harvestable power from each of the solarpanels 10.

As well, some embodiments of the DMPPT modules 18 may preferably bereprogrammable or updatable, such as over the communications link 22,wherein different algorithms may be sent and stored within the DMPPTcontrollers 80, such as for modifying start up, operation, safety andshutdown operations.

DMPPT modules 18 also help to reduce the effects of partial shading onsolar arrays 34. In conventional solar panels, partial shading of asingle cell 12 causes the entire panel and string in which it isconnected to reduce power output, and also increases loses due to stringmismatch, by lowering the MPPT point for an entire solar array. Incontrast to conventional panels, the DMPPT modules 18 can controllablycompensate for partial shading at the panel level, to boost the DCoutput signal 102 o.

Test Platform.

A test platform was installed to test the benefits and operation of theDMPPT modules 18. The test bed utilized forty-eight solar panels 10,rated at 170 watts, connected in six strings of eight 170-watt panelseach. FIG. 12 is a schematic layout view 140 of the exemplary test bedsolar array 34 comprising a plurality of solar panels 10, wherein aportion of the panels in one or more strings further comprise DMPPTmodules 18. A first group 142 a comprising three strings 36 a,36 b and36 c having different sample orientations across the array 34 includedDMPPT modules 18, while a second group 142 b comprising three strings 36d,36 e and 36 f having different sample orientations across the array34, did not include DMPPT modules 18.

The system was connected to two identical conventional solar inverters144, e.g. 144 a,144 b for connection to a public AC grid, wherein thefirst string group 142 b was fed into the first conventional inverter144 a, and the second string group 142 b was fed into the secondconventional inverter 144 b. In the test platform 140, each of theconventional solar inverters 144 a,144 b was rated at 4,080 Watts PeakDC.

FIG. 13 shows the relative proportion and size of an exemplary solararray having a capacity of approximately 170 W, comprising a pluralityof enhanced solar panels, wherein a portion of the panels in one or morestrings further comprise DMPPT modules 18.

The panels on the test bed are laid out to give a fair representation ofsolar illumination. One half of the panels are modified with the DMPPTmodules 18, while the other half of the panels are left unmodified, i.e.standard solar panels. Each set feeds into a similar sized solarinverter from the same manufacturer. Data is to be gathered over aperiod of time to evaluate specific design parameters for the DMPPTmodules 18. Since the strings 36 are set adjacent to each other, shadingcan be introduced upon the system, such as by using cardboard cutoutsand sliding them over the top the solar panels 10.

Enhanced Inverter System Operation and Monitoring.

FIG. 14 is a block diagram of an exemplary system 40 comprising amodular power inverter housing 50 housing having one or more enhancedinverter modules 54, e.g. 54 a-54 j, a central interface 152, a database154, and connectable 155 to one or more local or remote monitoring orcontrol devices 156,160, such as for interaction with a user USR.

In some system embodiments, the modular power inverter housing 50 ispowered by the AC bus 56, e.g. such as by the AC grid 58, wherein thehousing 50 may be powered by a public AC grid 58 even when the powerarray(s) 34 are down. In other system embodiments 40, the modular powerinverter housing 50 is powered by the DC bus 42, 52 e.g. such as by thesolar arrays(s) 34, wherein the housing 50 may be powered off-grid, evenwhen the AC grid 58 is down. In some alternate system embodiments, themodular power inverter housing 50 is powered either off-grid 42,52 oron-grid 58, such as depending on available power.

As seen in FIG. 14, a central monitoring and control interface 152interacts with each of the inverters 154, e.g. the enhanced inverters 54a-54 j. Each of the enhanced inverters 54 preferably comprise adedicated server 55 (FIG. 5, FIG. 6), e.g. an embedded web server 55, ormay communicate with a system server 153, e.g. an embedded system server153, associated with the inverter housing 50.

The data collected from the power panels 10, e.g. the solar panels 10,the enhanced inverters 54, e.g. solar inverters 54, and other equipmentwith the system 40, can be displayed in near real-time, such as througha local device 156 or remote device 160, e.g. over a network 158, suchas but not limited to a local area network (LAN) a wide area network(WAN), or the Internet. This collected data can also be sent, such asthrough a server 153, and logged into a database 154. The exemplarysystem 40 seen in FIG. 14 may therefore preferably provide detailedtrending analysis and/or performance tracking over the lifetime of thesystem. The system server 153, e.g. an embedded web server 153,typically gathers information and provides presetting of controls forthe entire system 40, right down to the individual panels 10, throughcommunication links 22 to panel DMPPT modules 18.

The DMPPT module controller 80 (FIG. 7), e.g. such as comprising adigital signal processor 80, typically outputs data in a slave mode,such as by reporting data back to an associated embedded server 54 whenrequested, through one of several means, e.g. such as but not limited towired or wireless transmission 22. The controller 80 also typicallyaccepts measured parameters from the embedded controller 54 pertainingto the local ambient temperature 25 (FIG. 1) and the solar insolation,i.e. the intensity of incident solar radiation These parameters, alongwith the data collected at the panel 10, provide control inputs to theprogram performing the MPPT function on a distributed, i.e. local panel,level.

In some system embodiments 40, the communication links 22 between theDMPPTs 18 and the embedded server(s) 153,55 comprise either a multi-dropsingle twisted pair RS-485 communications line 22, or a wireless radiolink 22. In some system embodiments, the use of wireless communicationlinks 22 may be preferred, such as to reduce the wiring cost, therebyreducing the overall cost of the system 40.

In some embodiments, the protocol used for the communication links isModBus, such as RTU RS485 for the wired system, or a wireless tree meshsystem with self-healing/discovery capabilities for wirelesscommunication links 22. Such ModBus protocols are preferably designedfor harsh environments, minimizing or eliminating lost packets of data.

All distributed data is gathered and passed 22, e.g. via the RS-485ModBus links 22, and then the embedded server 54 at the inverter cabinet50 formats this into a viewable web page 157 (FIG. 14) for the user USR.This collected data can also be streamed out to another server, e.g.156,160 for data logging and trending applications.

The heartbeat signal rides on the universal broadcast address, and thissynchronizes all of the panels 10 within a few microseconds of eachother for their operation. Another defined address broadcasts theambient temperature and solar insolation from the server 153 to each ofthe DMPPT Modules 18. If communications are lost, or if a “Fire” signalis broadcasted, then the DMPPT Modules 18 automatically shut down, toremove high voltage from their input 72 and output 90.

Modular Design of Solar Inverter Units.

FIG. 15 is a block diagram of a modular inverter housing 50, such as aModel No. ASPM-2-70KW, available through Accurate Solar Systems, Inc. ofMenlo Park Calif., having two 35 KW enhanced inverters 54 installed,such as a Model No. ASPM-1-35KW, available through Accurate SolarSystems, Inc. of Menlo Park Calif., having a total rating of 70 KW. FIG.16 is a block diagram of a modular inverter housing 50 having three 35KW enhanced inverters 54 installed, e.g. Model No. ASPM-1-35KW, ratedfor 105 KW. FIG. 17 is a block diagram of a modular inverter housing 50housing having four 35 KW enhanced inverters 54 installed, e.g. ModelNo. ASPM-1-35KW, rated for 140 KW. While the exemplary enhancedinverters 54 described above are rated at 35 KW each, some alternateembodiments of the enhanced inverters are rated 4 kilowatts each,wherein the system 40 can operate even closer throughout the day.

The modular inverter housing 50 may preferably house a plurality ofinverters 54, to reduce cost, increase efficiency, and improveperformance of the system 40. As well, the use of a modular enhancedinverter 54, such as but not limited to a 35 kW inverter 54, is readilycombined or stacked to provide a wide variety of capacities for a system40, such as for a 35 kW system, a 70 kW system 40, a 105 kW system 40,or a 140 kW system 40, which may be housed in one or more types ofmodular inverter housings 50.

Each cabinet 50 typically comprises associated transformers, outputcircuitry, input circuitry, and communications 151 with the embedded webserver 153. The smallest current cabinet 50 houses a single 35 kW module54. The next step is a larger cabinet 50 that houses between two andfour of 35 kW enhanced inverter modules, depending on the powerrequired.

In the modular inverter housing systems 50, such as seen in FIG. 15,FIG. 16 and FIG. 17, if an enhanced inverter 54 goes down, the otherscontinue to deliver power to the AC bus 58. Therefore, a single faultwill not bring the entire system 40 down. The enhanced inverter units 54communicate with each other, such as through the embedded web server153.

In some system embodiments 40, one of the enhanced inverters 54initially comes on as the system 40 starts up, such as to increaseefficiency. As the available power increases, the next enhanced inverterunit 54 is signaled to come online, and so on, such that the system 40operates at near peak efficiency for as much time as possible, therebyproviding more system up time in larger systems. Therefore, in somesystem embodiments 40, the use of multiple enhanced modules 54 wastesless energy, as the system 40 only turns on inverters 54 that can besupported by the array 34.

In the modular inverter housing systems 50, such as seen in FIG. 15,FIG. 16 and FIG. 17, each of the enhanced inverter modules 54, e.g. suchas but not limited to being rated at 4 kW or 35 kW apiece, maypreferably be hot swappable.

Advanced Diagnostics and Monitoring of Enhanced Power Systems.

Since embedded web servers 153,55 communicate with the solar inverters54, the solar panels 10, and any other associated equipment, the system40 may preferably provide a near real-time view of the current status ofthe system 40 as a whole. If a problem occurs, then the operator USR isnotified by various means, e.g. such as through the user interface 157.

Most conventional solar power inverter systems typically provide asingle DC input voltage and a single current measurement at the inverterlevel, which is based upon the sum of an entire array. In contrast,while the enhanced power inverter system 40 provides the current,voltage, and power of each of the arrays 34, the enhanced power invertersystem 40 may preferably provide the status and performance for eachindividual panel 10 and string 36, such that troubleshooting andmaintenance is readily performed.

Smart Switching Technology.

FIG. 18 is a simplified schematic circuit diagram of an exemplary powersection 180 for an enhanced inverter module 54, wherein the enhancedinverter 54 uses a three-phase half bridge IGBT driven power stage, suchas provided with IGBTs 192, driver cards 188, and fiber optic links 190.

Most conventional inverter systems use a standard high frequency pulsewidth modulation (PWM) method that, while it performs basic signalinversion, has many inherent disadvantages.

FIG. 19 shows a resultant output power signal pulse train 200, basedupon active elimination of harmonics by an enhanced inverter module 54,wherein the power signal is processed using sine weighted pulses. In theenhanced pulse width modulation (PWM) provided by the enhanced invertersystem 54, some of the edges, e.g. 204,206, are dynamically linked toother edges in the firing sequence. This has the benefit of simplifyingthe overall inverter 54, as well as actively eliminating all thirdharmonics. The enhanced inverter system 54 reduces or eliminatesharmonics, by controlling where the rising edges 204 and falling edges206 of the pulse train 200 occur.

Combining these two features, it is possible to generate a modifiedsmart switching PWM signal 200 that has very low harmonic content, alower carrier switching speed, and improved efficiency. This switchingscheme 200 allows a relatively simple filter 356 (FIG. 26) to be used,which reduces weight and cost, and improves efficiency.

The cutoff point for the filter 356 is preferably designed for thenineteenth harmonic, thus improving vastly over conventional pulse widthmodulation methods. For example, for an enhanced 35 kW inverter design,the power savings from switching alone ranges from about 650 Watts to 1kW of power.

For example, the following equation provides the third harmonics of aseven pulse modified PWM waveform, as shown:

H03=(cos(p1s*3*pi/180)−cos(p1e*3*pi/180)+cos(p2s*3*pi/180)−cos(p2e*3*pi/180)+cos(p3s*3*pi/180)−cos(p3e*3*pi/180)+cos(p4s*3*pi/180)−cos(p4e*3*pi/180)+cos(p5s*3*pi/180)−cos(p5e*3*pi/180)+cos(p6s*3*pi/180)−cos(p6e*3*pi/180)+cos(p7s*3*pi/180)−cos(p7e*3*pi/180)+0)/(a01*3);

where “a01” is the power of the fundamental waveform, p stands forpulse, the number next to p indicates the number of the pulse, s standsfor the start of the pulse, and e stands for the end of the pulse, e.g.p1s indicates the start of the first pulse, and p1e indicates the end ofthe first pulse. Also, the first three pulses and the ending fifth pulseare linked to the others, to eliminate the third harmonics.

A microprocessor 352 (FIG. 26), such as located at a server 153 embeddedwithin the inverter housing 50, generates a calculated smart switchingpulse train signal 200, such as shown above. The calculated smartswitching pulse train signal 200 is then passed 366 (FIG. 27) to thedriver cards or boards 188, such as through fiber optic links 190 or viacopper wire 190. The driver boards 188 then convert these digital pulses202 (FIG. 19), e.g. 202 a-202 g, into power driving signals for theIGBTs 192. The IGBTs 192 controllably follow the turn-on pulses 204 andturn-off pulses 206 of the original smart switching pulse train signal200, thus switching the high DC Bus voltage. This switching power isthen transformed to the AC grid voltage 58 by a transformer 355 (FIG.26) and a relatively small filter 356 (FIG. 26). The resultant outputsine wave is very low in distortion. The use of smart switching 200inputs to the enhanced inverters 54 therefore reduces power loss,reduces harmonics, reduces filter requirements, and reduces cost.

Controller and Power Supply.

As described above, each of the DMPPT modules 18 are typically poweredfrom their respective solar panels 10, such as to reduce the wiringrequirements and improve the overall efficiency of the system 40. FIG.20 is a schematic circuit diagram of an exemplary self-power section 220of a DMPPT module 18, which generates local control voltage for theDMPPT module 18 from the solar panel 10.

In some embodiments, when the solar panel 10 begins generating about 4.5to 6.5 volts DC, there is enough power to start the DMPPT module 18. Oneof the benefits realized by this configuration is that the system 40 asa whole can wake up automatically, off the external AC grid 58. For asystem 40 configured with externally mounted solar panels 10 that areexternally mounted on the surface of the Earth E, e.g. such as but notlimited to stand-alone panels 10 or building-mounted panels 10, the userUSR is able to observe this wake up phenomena as the sun S rises in themorning, and as it sets in the evening, when the DMPPT modules 18 shutdown for the night.

Boost Circuits for DMPPT Modules.

FIG. 21 is a schematic circuit diagram of an exemplary boost circuit 250for a DMPPT module 10.

Voltage and Current Monitoring for Distributed Multi-Point Power PointTracking Modules.

FIG. 22 is a schematic circuit diagram of an exemplary current sensor270 for a DMPPT module 18, such as implemented by a V/I monitor 82 (FIG.7) and associated hardware, e.g. a current loop 83 (FIG. 7). FIG. 23 isa schematic circuit diagram of an exemplary voltage sensor 290 for aDMPPT module 18. The output voltage and current are reported back to theembedded server 153 at the inverter cabinet 50, while used locally bythe DMPPT controller 80 (FIG. 7) to provide stable regulated output 90for the DC distribution bus 42,52 (FIG. 5, FIG. 6). The input voltageand current are used by the on-board controller 80, e.g. DSP, as part ofthe multi-level MPPT program.

The output voltage also plays into this control loop. A Hall-effectDC/AC current module and a 10M ohm voltage dividing resistor networktransforms these signals to an op-amp for scaling, and are thenprocessed by the controller 80, e.g. DSP 80. This forms the basis of aper panel monitoring system.

System Safety and Use of Crowbar Circuits.

FIG. 24 is a schematic circuit diagram of an exemplary output safetyswitch 310 for a DMPPT module 18. FIG. 25 is a schematic circuit diagramof an exemplary crowbar circuit 330 for a DMPPT module 18. The enhancedsolar panel 10, such as seen in FIG. 1, preferably providessurvivability from an output short circuit. As seen in FIG. 7, an inputcrowbar circuit 96, triggered by the microprocessor 80, is placed acrossthe incoming power leads from the panel 10. In case of a fire, or anyother maintenance procedure that requires the system to be de-energized,the input crowbar circuit 96 is triggered, thereby shorting out thesolar panel 18. An output crowbar circuit 98 may also preferably beprovided, such as to charge down capacitors when the unit is shut down.

The crowbar circuits 96,98 may be activated for a wide variety ofreasons, such as for emergencies, installation, or maintenance. Forexample, during installation of the enhanced panels 10, the associatedDMMPT modules 18 prevent high voltage from being transmitted to theoutput terminals 19 a,19 b (FIG. 1), until the panel is fully installedinto the system 40. As well, if maintenance functions need to beperformed near or on one or more panels 10, one or more of the solarpanels 10 can be turned off, such as by triggering the crowbar circuits96,98 through the DMPPT controllers 80.

The crowbar circuits 96,98 conduct and hold the solar panel 18 in ashort-circuit condition until the voltage or current falls below thedevice's threshold level. To re-activate the solar panel 10, the currentis typically required to be interrupted. This can typically be doneeither by manually breaking the circuit, or by waiting until thesunlight fades in late evening. This means that the system automaticallyresets its DMPPTs 18 during a period of darkness, e.g. the night.

Currently, one of the most cost effective crowbar circuits comprises asilicon controlled rectifier (SCR) 330. This allows the crowbars 96,98to continue to function, even though the main circuits control power hasbeen shorted. This removes the danger of high voltage DC power from thepersonnel, e.g. on a roof of a building where solar panels 10 areinstalled. The DMPPT system 18 automatically resets itself during thenight, thus allowing for the completion of the work. If it is necessaryfor another day, the system 40 can operate in one of two modes. In afirst mode, such as when communications 22 are present with the host 50,the host 50 can instruct the DMPPT devices 18 to shut down, thusallowing another period of safe work, e.g. on the roof. In a secondmode, such as when there are no communications 22 with the host 50, theDMPPT module 18 may preferably fire, i.e. activate, the crowbardevice(s) 96,98. To prevent unnecessary shutdowns, thisnon-communication method may preferably only occur if a status bit hasbeen saved, e.g. in EEPROM memory at the module 18, indicating a fire ormaintenance shutdown.

The current crowbar circuit 330 implemented for the DMPPT Module 18 isan SCR with its associated firing circuitry. The main control software,e.g. within the system server 153, preferably allows for a maintenanceor fire shut down of the solar array system. This operates on a panelper panel basis, thus providing a safe solar array shutdown. The hostsystem housing 50 can display the current array DC voltage, to indicatewhen it is safe to enter the roof area. The host system housing 50 maypreferably be tied into the fire alarm system of the building, or may becontrolled by a manual safety switch located by the host system itself.This addition to the DMPPT Modules 18 therefore enhances overall systemperformance, and improves safety for personnel.

Enhanced Inverter Power Circuit Operation.

FIG. 26 is a schematic block diagram 350 showing microprocessor-basedpulse width modulation 354 of an enhanced inverter 54, such as toeliminate one or more levels of harmonics. FIG. 27 is flowchart of anexemplary PWM harmonic reduction process 360 for an enhanced inverter54. As seen in FIG. 26, a microprocessor 352 may preferably be used toprovide a driving signal 354 to each of the enhanced inverters 54. Forexample, as seen in FIG. 27, for a DC signal received 362 at theenhanced inverter 54, either the DC power 42,52 from the panels 10, orthe AC bus power 58, may be used to turn on 364 the power to theinverter transistors 192 (FIG. 18), which may preferably compriseinsulated gate bipolar transistors (IGBTs) 192. A special signal 354(FIG. 26), which may preferably comprise a smart switching pulse train200 (FIG. 19), e.g. such as but not limited to switching at 1.68 KHz, issent from the microprocessor 352 at the embedded server 153 (FIG. 14),to switch the DC bus through the driver cards 188 (FIG. 18) and provideactive elimination of one or more harmonics, such as to controllablyreduce or eliminate the harmonics from the DC signal, e.g. thirdharmonics 3, 9, 15, etc. The AC signal output 368 from the enhancedinverter 54 provides increased power over conventional inverter systems.

Since the inverter 50 is built in module blocks 54, for a larger system40 each inverter block 54 may preferably turn on when needed to increasesystem efficiency. Solid-state inverters 54 presently run better oncethey have more than about 45 percent load. Therefore, for a 140 kWsystem 40, as power increases through the day, a first module 54 willturn on to provide power until there is enough power for the secondmodule 54. The second module 54 will come on and the two modules 54,e.g. 54 a and 54 b will share the load (and still above the 45% point)until a third module 54 is needed. The same is true until all fourmodular inverters 54 are on. Later in the day, when power from the solararray 34 begins dropping off, each modular inverter 54 will drop off asnecessary, until the system 40 shuts down for the night. This keeps thesystem 40 running at peak efficiency longer than a single largeinverter, thus generating more power for the AC grid 58.

The use of smart switching of the inverters 54, as described above,delivers more power to the grid, since less solar power is convertedinto heat from the switching of the transistors. Furthermore, since asmaller filter is required (due to harmonic cancellation), there is morepower available for pumping to the grid.

Another benefit of the modular system 40 is redundancy. For example, ina system having more than one enhanced inverter 54, if one enhancedinverter 54 fails for some reason, the entire system 40 does not comedown. The system can continue to pump power out to the AC grid 58 withwhat capacity is left in the system 40.

FIG. 28 is an exemplary user interface 400, such as comprising a webpage 157 (FIG. 14), for monitoring and/or control of an enhanced powerharvesting system 40 comprising enhanced inverters 54, and power modules10 having DMPPT modules 18. The exemplary user interface 400 seen inFIG. 28 may typically comprise any of system, array and/or componentlevel status 402, control 404, logs 406 for one or more panels 10,system reports 408, and revenue tracking 410. For example, an exemplarysystem status screen 412 is seen in FIG. 28, such as to indicate currentoperating status of different strings 36 of solar panels 10.

As seen in FIG. 28, a first string 36 of panels comprises six panels 10,wherein panels 1-4 and 6 in the string are indicated 414 a as beingonline and OK, while the fifth panel 10 in the first string is indicated414 a as being a problem and is currently taken offline. As also seen inFIG. 28, a second string 36 of panels comprises six panels 10, whereinpanels 1-6 in the second string are indicated 414 b as being shutdownfor service, such as controlled 416 through the user interface 400.

The user interface 400 may typically be accessed through a wide varietyof terminals, such as directly through an embedded server 153, locallythrough a connected terminal 156, or at another terminal 160, such asaccessible through a network 158. In some embodiments, the system 40 mayprovide other means for alerts, status, and/or control, such as but notlimited to network communication 155 to a wireless device 160, e.g. suchas but not limited to a laptop computer, a cell phone, a pager, and/or anetwork enabled cellular phone or PDA.

As each of the panels 10 preferably comprises DMPPT functionality 18,wherein the DMPPTs provide monitoring at the panel level, the system 40is readily informed, such as over the communication links 22 between theDMPPTs 18 and the invertors 54 or housing 50, of the operating status ofeach panel 10 in any size of array 34.

Furthermore, the DMPPTs 18 similarly provide troubleshooting anddiagnostics at the panel level. For example, if there is a problem withone or more panels 10, such as not working, shut down locally by acontroller 80, dirty, or shaded, the system 40 will be informed over thecommunication links 22 of any and all panel-level information, and canalert the user USR. All information from the panels 10 is typicallylogged into a database 154, where performance, history trends, andpredications of future performance can be calculated. The database 154may preferably be connectable through a network 158, such as theInternet, i.e. the World Wide Web, wherein viewing, and even controland/or maintenance, may be done through a web browser at a remoteterminal 160.

As each enhanced panel 10 is connected to an associated DMPPT module 18,problems can be identified and pinpointed for both broken andsub-performing panels 10, wherein such panels 10 may readily be foundand replaced, i.e. the system 40 identifies the exact panel(s) with aproblem, thus significantly reducing the time required for repairs.

FIG. 29 shows an enhanced power harvesting system 40 located on theEarth E, wherein one or more panels 10 within a string 36 have differentangles (0, 45, 90) or orientations (E, W, N, S). Conventional solarpanels systems require solar panels having different angles of tilt tobe serviced by different inverters. However, since the output of theDMPPT modules 18 at the panel level can be regulated, enhanced panels 10having different tilt angles 422 can be fed into the same inverter, e.g.an enhanced inverter 54. The enhanced system 40 therefore allows panelsto be mixed, such by varying tilt 422, from flat (0 degrees) through 90degrees, and/or by varying directional orientation 424, by mixing East,West, South and/or North facing panels 10.

As well, since the output of the DMPPT modules 18 at the panel level canbe regulated, strings 36 having different lengths of enhanced panels 10may be fed into the same inverter, e.g. an enhanced inverter 54 or evena conventional inverter. For example, if one string 36 has an extrapanel 10, or shorts a panel 10, the DMPPT modules can adjust the outputof the remaining panels 10 in a string 36 to allow this “incorrect”string size to function in the system 40, without adverse affects.

Similarly, the use of DMPPT modules 40 allows different size panels ordifferent manufacturers to co-exist in the same array 34. Therefore,instead of having to buy all of the panels from a single manufacturer toreduce mismatch problems, the DMPPT allows the use of various panels andeven different wattages within the same system 40. Such versatilityprovides significant architectural freedom in panel placement anddesign, wherein solar panels equipped with an associated DMPPT module 10allow unique layouts to accommodate different architectural features onany building or facility.

Furthermore, the use of DMPPT modules 40 addresses panel and stringmismatch losses. At the present time, no two panels 10 are alike, andoften are specified with a plus or minus 5 percent rating. Whileconventional solar panel strings 36 operate only as well as the weakestpanel 10 in the string, the DMPPT modules 18 can adjust the output ofthe panels 10 to boost their output. Similarly, the DMPPT modules 18 fora string 34, such as controlled by the server over the communicationslinks 22, can boost the power as needed to reduce or even eliminatestring mismatch losses.

Block Diagram of Operation Software.

The software for the DMPPT modules 18 can be broken down into varioussections as most are interrupt driven. When the modules 18 wake up inthe morning, they each perform a routine check to ensure that everythingis functioning properly. The modules 18 preferably check the status of afire alarm flag, which is stored in EEPROM inside themicroprocessor/controller 80 of the DMPPT Module. The microprocessorcurrently implemented for the controller 80 includes FLASH, EEPROM, andSRAM memories on the chip.

While the modules 18 watch the communications line 22 for activity, suchas to see if the panel 18 needs to shutdown before power levels rise toa dangerous level. If necessary, the DMPPT Module 18 fires the crowbarcircuit 96,98 to remain off line. Otherwise, it will proceed to the waitstage, until enough power is available for it to perform its functions.

Multiple Power Inputs for the Enhanced Inverter Units.

Since the inverter design has been modified so that the MPPT has beenshifted to maximize harvest, the enhanced inverters, as well as theDMPPT modules may readily be adapted for different means of powergeneration, such as but not limited to fuel cells, wind power, Hydro,Batteries, Biomass, and Solar power. The inverters can operate at 50 Hz,60 Hz, or 400 Hz to cover a vast range of applications. The system canalso be designed for on-grid or off-grid applications.

While some embodiments of the structures and methods disclosed hereinare implemented for the fabrication of solar panel system, thestructures and methods may alternately be used for a wide variety ofpower generation and harvesting embodiments, such as for fuel cells orbatteries, over a wide variety of processing and operating conditions.

As well, while some embodiments of the structures and methods disclosedherein are implemented with a server 153 within the modular inverterhousing 50, other embodiments may comprise dedicated servers 55 withineach of the enhanced inverters 54, which may also be in combination witha housing server 153.

Furthermore, while the exemplary DMPPT modules 18 disclosed herein arelocated at each of the panels, dedicated DMPPT modules can alternatelybe located at different points, such as ganged together locally near thepanel strings 36. In present embodiments, however, the DMPPT modules 18disclosed herein are located at each of the panels 10, such as toprovide increased safety, since the crowbar circuitry 96,98 is locatedat the panel, and upon activation, no high voltage extends from thepanels on the output connections 21.

Enhanced Coated Power Panels.

The efficiency of solar panels falls off rapidly as dirt and otherimpurities settles on the outer, e.g. upper, surface of the panels. Theouter glass substrates 504 (FIG. 30) on the surface of solar panels 10,e.g. conventional solar panels 10 and/or solar panels having DMPPTmodules 18, typically contain microscopic voids, fissures, and/orscratches 506, making them rough, wherein dust, dirt, scale,particulates, and other contaminants can readily adhere to the glass504.

FIG. 30 is a partial cutaway view of an enhanced solar panel structure500 having a top coating layer 508. It is advantageous to provide suchimprovements to the outer optical structures 502,504 for solar panels10, such as to provide enhanced cleaning, and/or to provide improvedlight adsorption. Coatings 508 can be applied to any of:

-   -   used, i.e. existing, solar panels 10 (such as with pre-cleaning)    -   new but conventional solar panels 10, e.g. in the field (such as        with pre-treatment/cleaning); and/or    -   new enhanced solar panels 10, with enhanced coatings 508 applied        during production (before shipment).

In some embodiments, the coating materials 508 are described asnano-technology materials, as they provide enhanced cleaning and/orimproved light adsorption on any of a macroscopic or microscopic level.For example, the coatings 508 may preferably fill in or reduce voidsfissures, and/or scratches 506. As well, the coatings 508 may preferablyprevent or reduce buildup of dust, dirt, scale, particulates, and/orother contaminants on the solar panel glass 504.

In some embodiments, the enhanced coatings may preferably comprisehydrophobic coatings 508, e.g. comprising silicon oxide, and/orhydrophilic coatings 508, e.g. comprising titanium oxide.

For example a thin layer, e.g. such as but not limited to about 5,000Angstroms thick, of a hydrophobic coating 508, provides a surface towhich dust and dirt has difficulty adhering. One such hydrophobiccoating 508 currently used comprises a Teflon™ based coating 508,wherein incoming water, such as delivered 622,624, or by other means,e.g. rain, condensation, or fog, beads up on the glass 504, such as byreducing the surface contact between the liquid and the glass 504, andallowing the water to roll off, thereby accelerating the cleaningprocess.

The use of hydrophilic coatings 508, coupled with sunlight and moisture,may preferably react with deposits that land on the glass 504, such asto break down organic material to a point where it blows away in thewind, or washes off with water.

In some exemplary embodiments, the enhanced coatings may preferablycomprise hydrophobic coatings 508, e.g. comprising silicon oxide, and/orhydrophilic coatings 508, e.g. comprising titanium oxide.

Other exemplary embodiments of the enhanced coatings 508 comprise bothhydrophilic and hydrophobic components, such as to provide a coatingmaterial that provides any of reaction with and/or repelling incidentwater and/or contaminants.

Further exemplary embodiments of the enhanced coatings 508 maypreferably comprise a component, e.g. an interference coating 508, thatreduces the reflectivity of the glass 504, such as to allow more lightto penetrate the glass and strike the solar cell structure 502, toproduce more electricity.

Solar panels 10, e.g. such as conventional solar panels or solar panelswhich include DMPPT modules 18, may therefore be enhanced by any of awide variety of coatings 508, such as to repel water, absorb light,and/or break down organic material. Such enhanced coatings 508 maypreferably be used for any of reducing dirt buildup on solar panel glasslayers 504, reducing cleaning time, and/or increasing the level ofcleanliness achievable through cleaning procedures.

Rack Mounting Angles for Solar Panel Arrays Having Fluid DeliverySystems.

FIG. 31 is a simplified schematic view 520 of an array 34 of solarpanels 10, e.g. enhanced solar panels 10 a-10 n, such as assembled withone or more frame members 524, having a rack mounting angle ø 526. FIG.32 is a simplified schematic view of a first exemplary embodiment of afluid delivery system 600 a for an array 34 of solar panels 10, whereinthe array 34 comprises one or more strings 36, e.g. 36 a-36 n of solarpanels 10.

Fluid delivery systems 600, e.g. 600 a, may preferably provide any ofcleaning and/or cooling for one or more solar panels 10, such as byspraying 622 or otherwise distributing 624 water, which may furthercomprise a cleaner, over the incident surfaces 504 of an array 34 of oneor more panels 10.

As seen in FIG. 31, the exemplary panels have a rack mounting angle 526.Conventional solar panel arrays have commonly been mounted with a rackangle 526 greater than zero degrees, such as to provide an increase inpower harvest. For example, many solar panel arrays located in theNorthern hemisphere have a rack mounting angle of about 8-10 degrees.

A conventional array of solar panels that are installed flat on a flatroof can theoretically provide 100 percent coverage across the roof,while a conventional array of solar panels that are installed with aneight degree slope on such a roof provides about 90 percent coverage,because of the aisle typically required between racking systems, such asto avoid shading between racks.

Panel arrays that have substantially higher rack angles, e.g. 20degrees, have a higher front to back height ratio, which typicallyrequires a larger distance between the racking structural rows, therebyresulting in less room for panels, such as for a horizontal roofinstallation. e.g. about 70 percent coverage for a flat roof system.

In an enhanced power generation system 40 that includes a fluid deliverysystem 600, such as for cleaning and/or cooling, the rack angle 526 maypreferably be chosen for fluid movement 624, e.g. water run off, as wellas for power harvest.

For example, one current embodiment of an enhanced power generationsystem 40 that includes a fluid delivery system 600, installed in MenloPark, Calif., has a rack mounting angle 526 of about 8 degrees towardthe South, which serves to increase power harvest and also allowstesting of a fluid delivery system 600.

The specific rack angle 526 for a solar panel installation maypreferably be chosen to facilitate self-cleaning during rainfall,automated, i.e. robotic, cleaning 764 (FIG. 39), and/or automatedcooling 744 (FIG. 38), such as to reduce or avoid maintenance and/orcleaning problems associated with flat mounted panels 10.

For example, for the specific solar panels 10 used for theaforementioned installation, and as recommended for many fluid deliverysystems 600, a rack angle 526 of at least 10 degrees (toward the Southin the Northern hemisphere or toward the North in the Southernhemisphere) may preferably provide greater fluid movement 624, e.g.water run off 624, such as to decrease residual build up of impuritiesalong the surface and lower edges of the solar panels 10.

As the rack mounting angle 526 is increased, such as between 15-20degrees toward the Equator, fluid runoff 624 is increased, which canpromote fluid reclamation and avoid deposition of contaminants at thelower edges of solar panels 10. The increased rack angle 526 alsotypically allows for a higher total year round harvest of electricityfor installations that can accommodate such configurations, since in thewinter, the Sun is lower on the horizon, so the additional tilt 526 ofthe panels 10 allows more light to be harvested. Because the higherslope results in better cleaning there is a trade off between effectivecleaning and the concentration of panels on the roof.

The first exemplary embodiment of a fluid delivery system 600 a seen inFIG. 32 comprises a mechanism 602 a for delivering a fluid 606, e.g.water, such as for cleaning and/or cooling of one or more solar panels10. The storage tank 608 seen in FIG. 32 may initially be filled throughan inlet 609, such as through activation of a valve 607. The fluid 606may typically comprise water, and may also comprise a cleaning agent.The water may further be treated to remove any of contaminants orhardness, and may further be chemically treated, such as with but notlimited to chlorine, bromide, algaecide, etc.

The exemplary delivery mechanism 602 a seen in FIG. 32 comprises a pump610 that is controllable 612, such as in response to any of one or moretracked parameters, a set point, or an external signal 614. Fluid 606 iscontrollably pumped 610 through a supply line 604 to a supply manifold616, which is then controllably distributed to one or more distributionheads 620, e.g. spray heads or sprinkler heads 620. The fluid 606 istypically applied as one or more wash streams or mists 622, such as torinse the solar panels 10 for cleaning and/or cooling. The fluid 606travels downward 624 across the solar panels 10, such as due to the rackangle 526.

The exemplary fluid delivery system 600 a seen in FIG. 32 also comprisesa mechanism for recovering the fluid 606, such as comprising a gutter626 connected 627 to a drain manifold 628, which returns 632 toward thestorage tank 608. The return line 632 may preferably further comprise afilter 630, e.g. a leaf filter, such as for but not limited to removalof leaves, dust, and/or dirt.

FIG. 33 is a detailed schematic diagram 640 of a second exemplaryembodiment of a fluid delivery system 600 b for an array 34 of solarpanels 10. As seen in FIG. 33, the water delivery mechanism 602 mayfurther comprise one or more valves 642 and secondary manifolds 644,such as to controllably deliver fluid as needed, e.g. for cleaningand/or cooling, to one or more sections of solar panels 10, and/or tocontrollably isolate one or more sections of solar panels 10, such asfor delivery system maintenance.

The collection gutter 626 may further comprise a protective screen toprevent leaves or objects other than the water run off 624 from enteringthe system 600. The collection manifold 628 for the fluid deliverysystem 600 b seen in FIG. 33 may comprise a PVC pipe 628, e.g. 4 inchdiameter, having a series of defined holes 629, wherein periodicallyspaced drain pipes 627 extend into. The exemplary drain pipes 627 aremounted with bulkhead connections to the outer lower edge of a raingutter 626 that is attached along the lower edge of the series of solarpanels 10.

While the fluid delivery system 600 b is described herein as using sprayheads 620 as one example of cleaning and/or cooling, a wide variety ofstationary or mobile systems may be used, such as stationary sprays,rotating stationary heads, or even a movable track to spray along thelength, e.g. from top to bottom, moving sideways.

As also seen in FIG. 33, the return line 632 may also preferablycomprise any of a recirculation pump 646, and inline shutoff 648, afilter 648, and/or a water meter 652.

In some embodiments 600, the filter 650 preferably removes or reduceslevels of minerals, salts, and/or other contaminants from the fluid 606,e.g. water 606, such as depending on available water supplies. In onecurrent embodiment of the fluid delivery system 600, the filter 650comprises an ELYSATOR 15™ water conditioner, available throughInternational Water Treatment of North America, such as to removecalcium and other minerals from the water 606, before the water 606 isreturned to the storage tank 608.

One current embodiment of the storage tank 608 comprises a 300 gallonreservoir filled with tap water 606, which is pumped from the storagereservoir 608 to a four inch PVC water pipe 616 that runs along thelength, e.g. 90 feet, of the racked array 34. Every thirty feet, a oneinch pipe 644 is tapped off of the four inch pipe 616 through a solenoidoperated valve 642. Each of the secondary manifolds 644 feeds threesprinkler heads 620 that wash the panels 10.

The water spray 622 from the spray heads 620 cascades 624 down thepanels 10 and into the rain gutter 626, which empties into a collectionmanifold 628, e.g. a 4-10 inch irrigation pipe. The collected water 624flows through the collection manifold 628 and through a primary filter,e.g. a leaf filter 630, which filters out large particles. The water ispiped down 632 into the storage tank 608, and also is teed to arecirculation pump 646, e.g. a 30 watt pump 646, that feeds thesecondary filter 650. The recirculation pump 646 may preferablycontinuously circulate the water 606 in and out of the storage tank 608,e.g. through a recirculation line 656, such as for continuous waterfiltration, i.e. polishing, by the secondary filter 650.

In one current embodiment of the solar power generation system having afluid delivery system 600 b as seen in FIG. 33, the distributionmanifolds 644 are segmented into three 30 foot lengths, to accommodatethree rows of panels 10, with a string of 11 panels in each row for a 33panel test group. Each of the panels 10 has a monitoring box 18 attachedthat monitors voltage, current and temperature of the panel, and alsoallows the panel to be shut down in case of emergency or need ofmaintenance. This information is accessed from the panel through awireless transmitting system, transmitted directly to a computer thatdisplays all the vitals for each panel.

This 99 panel test system is divided up into three 33 panel sections,wherein each of the panels have been coated with nano-technologymaterial 508, but were not initially washed, to start to gather dirt,which fell on these panels throughout the day and at night. When dewgathered, the dew wet the dirt, causing it to flow down the panels 10and catching at the bottom of the panel against the aluminum edge wereit sticks because there was not enough water volume in the dew to washthe dirt off the panel.

The installed system therefore provides some minimal washing of the dewitself, on its own, but the dirt gathered at the bottom because therewas not sufficient water to completely flush it.

When such dirt settles across the bottom of a panel, such dirt may getthick enough to block out as much as 5 percent of the panel, whichcauses as much or more than a five percent decrease in power productionfrom the entire string, because on a per panel basis, such an effectedpanel becomes a weak link.

For solar panel systems that are monitored on a per panel basis, i.e.not on a per cell basis, if the performance of one section of the panel10, e.g. the lower edge, loses efficiency, e.g. such as by five percent,the efficiency of the entire panel 10 is reduced by five percent.

In the aforementioned system, all 99 panels were monitored, such as forperformance testing. On the first 33 panel test section we are going toevaluate the effects of cooling the panels to generate additionalelectricity output. The cooling was provided by incrementally runningwater over the panels from early in the morning until late in theafternoon.

In some embodiments of the fluid delivery system 600, such as forinstallations having solar panels that are enhanced with a protectivecoating 508, compressed air may be used to blow loose dirt and dust fromthe panels 10, such as to minimize the use of water 606. As well, watermay be used during the evening or at night, e.g. for periodic extracleaning), such as to minimize evaporation during daylight hours.

FIG. 34 is a simplified schematic view 660 of a third exemplaryembodiment of a fluid delivery system 600 c for an array 34 of solarpanels 10. In some system environments, such as where clean water isplentiful and cost effective, without either a need or desire forreclamation, a simplified fluid delivery system 600, e.g. 600 c, mayprovide sufficient water for cleaning and/or cooling purposes. The fluiddelivery system 600 c seen in FIG. 34 comprises a fluid deliverymechanism 602, such as comprising a valve 642 that is responsive tocontrol 612, typically in response to any of one or more trackedparameters, a set point, or an external signal 614. The fluid 606, e.g.water is sprayed 622 through spray heads 620, and runs off 624 theinclined solar panels 10 at the lower end, such as through a gutter 626and a drain manifold 628.

The fluid delivery system 600, e.g. such as comprising a roboticwatering system 600, is therefore typically installed along the top,i.e. upper end 530 a (FIG. 31) of the racking system 34, and provides aslow cascade 624 of water 606 that runs down the face of the panels 10,such as at an optimized interval, or based upon a tracked parameter 614,to keep the power generation system 34 operating at maximum efficiency.Water 606 caught at the base of the racking 34 may preferably berecovered, e.g. such as through a manifold 628, filtered 650, and pumpedback into the storage tank 608 for the next cleaning and/or coolingcycle.

In areas where the water contains calcium and other harsh chemicals thatmay be harmful to the panel, the water treatment 650 may also preferablycomprise de-ionization. As well, an additional boost in electricaloutput may often be gained by cooling the panels 10 during the heat ofthe day, as the panels decrease output when exposed to highertemperatures.

FIG. 35 is a schematic block diagram of an exemplary fluid distributionsystem 600 integrated with an exemplary solar panel system having aplurality of strings 36, e.g. 36 a-36 n, of enhanced solar panels 10,such as having dedicated DMPPT modules 18, that are routed through acombiner box 48 and controlled through a modular power module housing 50having one or more enhanced inverter modules 54. Since the distributedmaximum power point tracking system, structure and process providesmonitoring, control, and isolation of individual panels within a solarsystem, further enhancements can be made to provide enhanced systemefficiency.

For example, for the enhanced power generation system shown in FIG. 35,each panel 10 preferably comprises a module 18 that can monitor any ofvoltage, current, and/or temperature, and also preferably comprises amechanism by which the panels 10 may be individually shut down, such asfor emergencies. The individually monitored panels 10 preferably allowthe output of each panel to be tracked. In some embodiments, when theefficiency drops by as much as 5 percent, the fluid delivery system maycontrollably be activated 764 (FIG. 39) to clean the panels 10. Theenhanced power generation system shown in FIG. 35 is fully automated,such that workers are not required to access the roof for cleaning,thereby saving labor, water and insurance costs, while ensuring fullproduction out of each solar panel 10 year round.

Environmental Effects on Solar System Performance.

FIG. 36 is a chart 700 that shows power reduction as a function of dirtaccumulation 704 for a solar panel structure. Solar panels lose powertherefore electrical output as a function of dirt accumulation. Thestandard wattage output for solar panels is tested at the factory withclean panels, such as to define a rated power 706, as tested at acontrolled temperature, e.g. 25 degrees Celsius. In the field, however,as dirt accumulates on some or all of the surface of a panel 10, theactual power 708 decreases, i.e. is reduced 710, from its rated value,such as by as much or more than 5-6 percent of its rated value

For example, especially for panels that are not enhanced with a coating508 (FIG. 30), dirt and/or scale can build up along the bottom end 530 b(FIG. 31) of solar panels 10, to the extent that the sunlight is reducedfrom reaching and being fully absorbed by the panels 10. This causes theentire panel to drop in voltage output by as much as from five to twentyfive percent, depending on how severe the build-up is.

The use of a protective coating 508 on the incident surface 532 a of thesolar panels 10 allows the panels 10 to remain cleaner for a longerperiod of time, as the enhanced panels are resistant to a build up ofdirt and/or scale, such that even before cleaning, the treated panels 10have a higher electrical output than untreated panels. As well, theenhanced panels are more quickly and more thoroughly cleaned by thefluid delivery system, yielding higher power production for one or moreof the solar panels 10.

FIG. 37 is a chart 720 that shows power output as a function oftemperature 722 for a solar panel structure 10. Solar panels loseefficiency and therefore electrical output as a function of temperature.The standard wattage output for solar panels is tested at the factory at25 degrees Celsius. For every Centigrade rise in temperature over arated temperature, the panel's electrical output may typically decreaseby ˜0.5% of the rated output.

It is not uncommon, in warm weather, for the panel temperature to risefrom about 25 degrees Celsius to about 83 degrees Celsius, as measuredon the incident surface 532 a of a solar panel 10. This 58 degree risein temperature, based on an approximate 5 percent of rated output power,results in a total loss of approximately 58 watts on a 200 watt panel,e.g. a loss approaching 30 percent. This estimated loss is based on anabsolutely clean panel 10. However, for common situations with a similar83 degrees Celsius of heat on the panel, in addition to accumulateddirt, such an exemplary solar panel may lose an additional 25-30 watts,resulting in 110 watts of output power for a solar panel 10 that isnominally rated at 200 watts, because of the combined effects of heatand dirt. Therefore, depending on the environment, the fluid deliverysystem 600 may be used for any of cleaning and/or cooling of the panels10.

Enhanced Operating Processes for Fluid Delivery Systems Integrated withSolar Panel Systems.

FIG. 38 shows a simplified process 740 for activation of a solar systemcooling system based upon temperature monitoring. For example, while asolar panel system is operating, the temperature of one or more panels10 may preferably be monitored 742. The fluid delivery system 600 may becontrollably activated 744 when one or more of the tracked temperaturesexceed a setpoint, e.g. 120 degrees F. The fluid delivery system 600 mayoperate for a set period of time upon activation 744, or may shut down746 if and when a lower setpoint is reached, e.g. 70 degrees F., orwithin a certain threshold as compared to ambient temperature. In systemembodiments wherein one or more panels 10 are monitored, such as forsystems including DMPPT modules 18, the temperature may preferably bemonitored through the temperature sensor (e.g. thermometer,thermocouple, RTD, etc.) on each panel 10, and at the appropriate timeand temperature, the system can controllably turn on the water forcooling. As an example, at a high setpoint, e.g. 90 degrees F., thecontrol may trigger the system to turn on, and when the temperaturedrops to a low setpoint, e.g. 65 degrees F., the cleaning system 600 maypreferably turn off.

FIG. 39 shows a simplified process 760 for activation of a solarcleaning system based upon efficiency monitoring. For example, while asolar panel system is operating, the efficiency of one or more panels 10may preferably be monitored 762. The fluid delivery system 600 may becontrollably activated 764 when one or more of the tracked efficienciesdecreased below a setpoint, e.g. below 90 percent of rated power for agiven temperature. The fluid delivery system 600 may operate for a setperiod of time upon activation 764, or may shut down 766 if and when aefficiency exceeds an allowable efficiency setpoint.

Solar Array Seal Structures.

FIG. 40 is a partial cutaway view 800 of a first exemplary sealstructure 806, e.g. 806 a between enhanced solar panels 10. FIG. 41 is apartial cutaway view of a second exemplary seal structure 806 b betweenenhanced solar panels 10. FIG. 42 is a partial cutaway view of a thirdexemplary seal structure 806 c between enhanced solar panels 10.

As the fluid delivery system 600 is typically installed to provide waterfor cleaning and/or cooling, and as the water may preferably berecovered, stored and reused, arrays of solar panels 10 may preferablyfurther comprise a sealer structure of sealant 806 at boundaries 804between solar panels, e.g. such as between the bottom edge of one panelsand the upper edge of an adjoining panel, and/or between the sides ofadjoining panels 10.

The exemplary seal 806 a seen in FIG. 40 may preferably comprise anapplied silicone based sealant, such that water doesn't leak down andescape through the boundaries 804.

Similarly, the exemplary seal 806 b seen in FIG. 41 may preferablycomprise one or more structures, such as applied silicone based sealant,and/or suitable sealant strip material, e.g. having a thickness 822, toprovide any of a top seal 826 and/or a lateral seal 828.

The exemplary seal 806 c seen in FIG. 42 may preferably similarlycomprise an applied silicone based sealant, such that water doesn't leakdown and escape through the boundaries 804. As seen in FIG. 41, theenhanced solar panels 10 provide a frame 802 that is substantially flushto the combined height of the solar panel glass 504, which may alsopreferably have a coating layer 508, wherein the substantially flushinterface may promote water runoff 624 and prevent any pooling along thebottom edge of a solar panel 10, e.g. such as to reduce build up of dirtand/or scale. The enhanced solar panels may therefore preferably includeframes 802 that are flush to the glass substrate, at least for the upperand lower sides of the frame 802, such that dew, rain, and coolingand/or cleaning water can readily drain off toward the lower edge,wherein water is not accumulated upon the lower edge of each solarpanel. In some embodiments, such frames are flush around the entireperimeter of the solar panel. The use of flush frames prevents anyresidual dirt and impurities from settling and drying along the loweredge of the panel, which could otherwise decrease the power output ofthe lower cells, and consequentially lower the entire output of thepanel. As also seen in FIG. 41, the frames 802 may also include arecess, e.g. such as a bevel or radius 842, wherein a seal 806, e.g. 806c may be applied and still retain a substantially flush interface.

The material for the seals 806 may preferably be chosen for the expectedtemperature range and for other environmental conditions, e.g. exposureto Sunlight. Silicone sealant 608 is often rated for applications up to300 degrees F.

In contrast to prior cleaning processes, as applied to conventionalsolar panels in the field, the enhanced cleaning system 600 providesseveral improvements, such as for one or more solar panels 10, inhardware configurations, and/or in system operation parameters. Forexample, such an individual panel monitoring system can immediatelyidentify problem areas, such as related to dirt accumulation and/orelevated panel temperatures.

The fluid delivery system 600 and related structures and processespreferably provide several advantages for different environments, suchas but not limited to:

-   -   cleaning solutions and/or protective layers for solar panel        arrays;    -   application of cleaning solutions and/or protective layers, e.g.        for any of retrofitting conventional panels on site,        retrofitting new panels on site, and/or for new solar panels        provided with enhanced layers;    -   delivery systems for use on a solar array; such as with water,        treated water, and/or a cleaning solution, for any of cleaning,        cooling or any combination thereof;    -   delivery/cleaning system spray distribution, reclamation, and/or        filtering systems;    -   solar panel system layout or tilting for enhancement of delivery        system. e.g. improved cleaning, flushing, cooling, and/or        reclamation;    -   control parameters for a delivery system, e.g. such as linked to        a DMPPT system, with time, power output, and/or temperature        considerations; and/or    -   improved solar panel frames and/or seals, e.g. such as to        enhance cleaning, flushing, draining of any of a delivery system        or for any resident moisture (dew, rain, etc.), such as to avoid        buildup of dirt or scale., etc.

DMPPT Structure Details.

FIG. 43 is a schematic block diagram 900 of a solar panel system havinga plurality of conventional solar panels connected in a series form,connected to a simple (unmodified) inverter, to convert the DC voltagefrom the string to an AC waveform.

FIG. 44 is a schematic block diagram 920 of an alternate exemplary solarpanel system 40 having an arrangement of enhanced solar panels connectedin a parallel manner. The common bus that the panels are connected tocan be in the form of a stabilized DC bus, or a stabilized AC bus of asingle or three phase variety, of a chosen voltage level. The common busmay terminate at grid interconnection, a transformer, an inverter of theenhanced or unmodified form, or a battery charger or other DC powergrid. The panel enhancements perform the task of optimizing the outputof the solar panel and adding power to the common bus.

FIG. 45 is a schematic block diagram 940 of an exemplary solar panelsystem 40, e.g. 40 a (FIG. 5) or 40 b (FIG. 6), having a string ofenhanced solar panels having DMPPT connected in series, and controlledthrough a modular power module housing having one or more enhancedinverter modules. The control loop algorithms that the DMPPT enhancedpanels operate under to perform the optimization can take several forms,such as comprising, but not limited to any of:

-   -   stand alone operation;    -   string level loop closure;    -   combiner box level loop closure; and/or    -   enhanced inverter module level loop closure.

Additionally, the algorithms may preferably act to perform optimizationto provide any of:

-   -   DC bus string voltage stabilization as a constant; or    -   Current stabilization as a constant,        as may suit the conditions required for best total power output.

In an earlier installation of conventional solar panels, having a ratedcapacity of 400 KW, without individual monitoring provided by adistributed maximum power point tracking system, several outagesresulted in significant loss in power output over extended periods oftime. Monitoring of such a 400 KW system can save thousands of dollarsin electricity bills as incidences of panel failure, which areconventionally only discovered by manually inspecting the panels.

In the aforementioned system, these outages were caused by, in one case,a panel being hit by a rock, in a second case by a bullet and in twocases, panels that failed, due to hot spots burning through the coppertraces. As the system was initially installed without means formonitoring, there was no way of knowing how long these panels were outof commission, but they could have been down for six to eight monthsbefore detection. Not only did the system lose the performance of theafflicted panel, but also the weak-link effect brought down theperformance of several of the connected strings, exacerbating theproblem and loss of electricity.

The distributed maximum power point tracking system measures thevoltage, current, and temperature of the panel and wirelessly transmitsit to a web-based monitoring system. If any panel drops below a certainperformance level, the software sends an alarm indicating a problem.

In addition, the distributed DMPPT modules 18 ensure that fire andmaintenance crews remain safe when operating around solar systems, byallowing the panels 10 to be isolated using a remote system with afail-safe.

Accordingly, although the invention has been described in detail withreference to a particular preferred embodiment, persons possessingordinary skill in the art to which this invention pertains willappreciate that various modifications and enhancements may be madewithout departing from the spirit and scope of the disclosed exemplaryembodiments.

1. A liquid distribution system for a power generation system comprisinga plurality of solar panels, comprising: a server; a delivery mechanismfor distributing a liquid over the outer surface of at least a portionof the solar panels; a liquid delivery controller associated with thedelivery mechanism; and a plurality of panel controllers, wherein eachof the panel controllers is associated with a corresponding solar paneland is configured to track one or more operating parameters for thecorresponding solar panel, and to send a data signal to the server,wherein the data signal corresponds to the tracked parameters; whereinthe server is configured to monitor any of efficiency or temperature ofone or more of the solar panels based upon the received data signals,and to send a control signal to the liquid delivery controller when anyof the monitored efficiency is less than or equal to an efficiencysetpoint, or the monitored temperature exceeds a temperature setpoint;and wherein the liquid delivery controller is configured to activate thedelivery mechanism in response to the control signal.
 2. The liquiddistribution system of claim 1, wherein the delivery mechanism isactivated for any of cleaning or cooling of the solar panels.
 3. Theliquid distribution system of claim 1, wherein the liquid compriseswater.
 4. The liquid distribution system of claim 3, wherein the liquidfurther comprises a cleaning solution.
 5. The liquid distribution systemof claim 1, wherein the solar panels have an upper incident surface forreceiving incoming light, and wherein any of a hydrophilic orhydrophobic layer is applied to the upper incident surface of one ormore of the solar panels.
 6. The liquid distribution system of claim 5,wherein the hydrophilic layer comprises titanium oxide.
 7. The liquiddistribution system of claim 5, wherein the hydrophobic layer comprisesany of silicon oxide or a fluoropolymer.
 8. The liquid distributionsystem of claim 1, wherein the solar panels have an upper incidentsurface for receiving incoming light, and wherein one or more of thesolar panels further comprise an interference layer over the upperincident surface to promote light penetration toward the incidentsurface.
 9. The liquid distribution system of claim 1, wherein thetracked parameters comprise any of temperature, voltage, or power. 10.The liquid distribution system of claim 1, further comprising: arecovery system for collecting and storing at least a portion of thedistributed liquid.
 11. The liquid distribution system of claim 10,wherein the recovery system further comprises a filter for filtering thecollected distributed liquid.